• The certificate has been revoked. For example, the website’s owner might have requested that the certificate be revoked if the site was hacked. 
• The certificate was subscribed illegally. A certificate must be obtained from a special, authorized center (certificate authority) after undergoing the necessary checks. 
• The certificate chain is broken. Certificates are checked along a chain. The chain goes from a self-signed certificate to a trusted root certificate, which is provided by a certificate authority. Intermediate certificates are intended for signing another certificate in the chain.
  There are several reasons the certificate chain might be broken:
  • The chain consists of one self-signed certificate. A self-signed certificate is signed by the creator of the certificate itself. Such certificates are not authenticated by a certificate authority and might be unsafe.
  • The chain does not end with a trusted root certificate.
  • The chain contains certificates which are not meant to sign other certificates.
  • The root or intermediate certificate has expired or has not yet become active. Certificate authorities give out a certificate for a certain period of time. 
  • The chain cannot be built.
• The domain specified in the certificate does not match the website to which the connection is established.
• The certificate is not meant to confirm the node authenticity. For example, the certificate is only intended for the encryption of the connection between the user and the website.
• Usage policy violation. A certificate policy is a set of rules that determine the use of the certificate with specified security requirements. Every certificate should comply with at least one certificate policy. If multiple policies are in use, the certificate should comply with all of them. 
• Action time has either expired or is yet to arrive. Certificate authorities give out a certificate for a certain period of time. 
• The structure of the certificate is damaged.
• A signature verification error has occurred.

If you don’t want to receive warning messages about certificates, disable encrypted connections scanning.

1. In the main window of your Kaspersky Lab application, click .

1. To learn how to open the application, see this guide.

2. Go to the Additional section and select Network.

3. Select the Do not scan encrypted connections option.

4. Read the warning and click Continue.

The encrypted connections scanning has been disabled.

1. In the main window of your Kaspersky Lab application, click .

2. Go to the Additional section and select Network.

3. Click Manage exclusions. 

4. Click Add. 

5. Enter the URL of the website where the warning message appeared. Set the status as Active and click Add.   

The website has been excluded from encrypted connections scanning.

If you use Google Chrome to stream tabs via a Chromecast device, you may get the message “Cannot guarantee authenticity of the domain to which encrypted connection is established” after starting the browser. Click Continue.

If the message appears again, update your Kaspersky Lab application to version 19.0.0.1088 with Patch E:

1. Run the database update for your Kaspersky Lab application.
2. After the update has completed, reboot your computer.

To make sure the patch has installed, open your Kaspersky Lab application and click Support in the lower-left part of the application window. In the window that opens, you will see the full version number of the application with the letter e added to it.

If you added the website to the list of exclusions from encrypted connections scanning, but the warning message appears once again, restart your Kaspersky Lab application or reboot your computer.

If the error persists, submit a request with a detailed description of the issue to Kaspersky Lab technical support:

• Via My Kaspersky for Kaspersky Internet Security, Kaspersky Anti-Virus, Kaspersky Total Security, and Kaspersky Security Cloud. See the Online Help page for instructions.
• Via the Kaspersky Small Office Security Management Console for Kaspersky Small Office Security. See the Online Help page for instructions.